Process for treating hides



Patented May 1, 1934 UNITED srArEs raocnss FOR TREATING nmEs Herbert C.Reed, Stamford, Conn., assignor to Niacet Chemicals Corporation, acorporation of New York No Drawing. Application August 5, 1931,

Serial No. 555,370

13 Claims.

It is not always practical or feasible to conduct the treatment of thehides at the tannery in an uninterrupted sequence of operations. Forthis reason difficulties are encountered and losses occur due to theexcessive putrefaction of hides which are allowed to stand between thevarious ticularly prevalent in hides which have been bated and which arenot immediately processed further. Also, hides which are cured bysalting are frequently unfit for the production of certain types ofleather. For example, goat or kid skins from which white orlight-colored leather is to be prepared may exhibit dark stains whentanned due to the presence of iron impuritiesin the salt with which thehides are cured. These iron compounds, if not entirely removed byrepeated and protracted washings, are precipitated by the tanning agentand produce the objectionable stains.

These difliculties are largely avoided and novel benefits are derivedfrom the application of the process of the present invention to thetreatment of hides. The invention comprises, as

its principal feature of novelty, the application of treating agents notheretofore used for this purpose, and provides a simple, efficient andeconomical method for treating hides preliminary to tanning, all as morefully hereinafter described.

In practicing my invention, the hides, prior to or at the beginning ofthe tanning operations, are subjected to the action of an aqueoussolution of paraldehyde (paracetaldehyde, (CHaCHO) a), or paraldol(CI-I3.CI-IOH.CH2.CHO) 2.

This treatment preferably occurs at the tannery, but, in the case ofparaldehydamay occur immediately after flaying to replace other curingmethods. In general, the hides are soaked with or without agitation in abath containing from about 0.1% to 10% of either paraldehydepr paraldolbased on the weight of the hides. Lower concentrations of the treatingagent in the bath within the range indicated. and shorter immersteps intheir treatment. This spoilage is parsion times maybe used if the bathis thoroughly agitated.

The effect of this treatment is multi-fold; it cleanses the hides,preserves the hides, plumps and fulls them, and, at least in the case ofparaldehyde, exerts a beneficial preservative eifect upon certainvegetable tanning agents with which the hides may be subsequentlycontacted.

The application of the two treating agents of my invention follow eachother in nearly all respects. The principal difierence is in regard totheir use in conjunction with lime baths or lime depilatory treatments.Paraldol cannot be advantageously used simultaneously with suchtreatments because the paradol tends to react with lime. For this reasontreatment with paraldol should be carried out after the hides havereceived the lime treatment, or treatment with other strongly alkalinematerials.

The treatment with paraldehyde may occur at any time before tanningwhether it is before, 'after or during lime treatment.

The following examples are illustrative of the invention:

I. One hundred pounds of wet goatskins were placed in a drum containing3 pounds of paraldehyde and 9'7 pounds of water. The skins werethoroughly agitated in this bath for one hour and were then removed,allowed to drain, and were introduced directly into the tanning bath.

II. The process of Example I was varied by using 5 pounds of paraldehydeand pounds of water, and 30 minutes of agitation in the bath. Thecleansing and plumping efiects secured in each case were very similar.

Hides which have.been subjected to a hating treatment may be immediatelythereafter treated with paraldehyde in the manner described. Thistreatment cleanses and plumps the hides, and in addition, it preventsputrefaction, allowing the 95 hides to be transported or stored forconsiderable periods of time without spoilage. 4

Hides or skins which have been treated with paraldehyde or paraldolyield a higher grade of leather than similar hides which are tanned inthe same manner without the use of these agents. The treatment of myinvention plumps and fulls the hide, giving it rubbery feel, and causingit to become slippery an both the flesh and grain sides. The hides,after being treated with the 105 new treating agents, may be removedfrom the bath and then tanned or the tanning may be accomplished byadding a tanning agent to the treating solution thus avoiding thenecessity of transferring the hides to another hath. no

From the foregoing description it will be apparent that modifications ofmy new process are possible and are included within the scope of theinvention as defined by the appended claims.

I claim:

1. A process for treating hides preliminary to tanning operations whichcomprises soaking the hides in a bath containing asubstance of the groupconsisting of paraldehyde and paraldol.

2. A process for treating hides preliminary to tanning operations whichcomprises soaking the hides in a bath containing about 0.1% to 10% basedon the wet weight of the hides, of a substance of the group consistingof paraldehyde and paraldol.

3. A process for treating hides to obtain leather therefrom whichincludes the steps of soaking the hides in a bath containingparaldehyde, drying the skins, rehydrating the hides and finally tanningthe hides.

4. A process for treating hides to obtain leather therefrom wh'chincludes the steps of soaking the hides in a bath containing about 0.1%to 10% of paraldehyde based on the wet weight of the hides.

5. A process for treating hides to obtain leather therefrom whichincludes the steps of soaking the hides in a bath containing paraldehydeuntil the hides are plumped, and then adding a tanning agent to saidbath to convert the tissues of said hides into tough, imputresciblesubstances.

6. A process for treating hides to obtain leather therefrom whichincludes the steps of soaking the hides in a bath containing about 0.1,%to 10% of paraldehyde based on the wet weight of the hides until thehides are plumped, and then adding a tanning agent to said bath tocenvert the tissues of said hides into tough, imputrescible substances.

7. A process for treating hides preliminary to tanning operations whichcomprises agitating the hides in an aqueous bath containing about 3% ofparaldehyde, based on the wet weight of the hides until the hides areplumped and swelled.

8. A process for treating hides preliminary to tanning operations whichcomprises agitating the hides for about one hour in an aqueous bathcontaining about 3% of paraldehyde, based on the wet weight of thehides.

9. A process for treating hides to obtain leather therefrom whichincludes the steps of soaking the hides in a bath containing about 0.1%to 10% of paraldol based on the wet weight of the hides.

10. A process for treating hides to obtain leather therefrom whichincludes the steps of soaking the hides in a bath containing paraldoluntil the hides are plumped, and then adding a tanning agent to saidbath to convert the tissues of said hides into tough, imputresciblesubstances.

11. A process for treating hides to obtain leather therefrom whichincludes the steps of soaking the hides in a bath containing about 0.1%to 10% of paraldol based on the wet weight of the hides until the hidesare plumped, and then adding a tanning agent to said bath to convert thetissues of said hides into tough, imputrescible substances.

12. A process for treating hides preliminary to tanning operations whichcomprises agitating the hides in an aqueous bath containing about 3% ofparaldol, based on the wet weight of the hides until the hides areplumped and swelled.

13. A process for treating hides preliminary to tanning operations whichcomprises agitating the hides for about one hour in an aqueous bathcontaining about 3% of paraldol, based on the wet weight of the hides.

HERBERT C. REED.

